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Deciphering the Biodiversity-Production Mutualism

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Deciphering the Biodiversity-Production Mutualism TREE 2713 No. of Pages 10 Trends in Ecology & Evolution Opinion Deciphering the Biodiversity–Production Mutualism in the Global Food Security Debate Ralf Seppelt ,1,2,* Channing Arndt,3 Michael Beckmann,1 Emily A. Martin,4 and Thomas W. Hertel5 Without changes in consumption, along with sharp reductions in food waste and Highlights postharvest losses, agricultural production must grow to meet future food de- Increasing demands for agricultural mands. The variety of concepts and policies relating to yield increases fail to inte- commodities are resulting in more in- grate an important constituent of production and human nutrition – biodiversity. tensely managed landscapes. This is at odds with biodiversity conservation and We develop an analytical framework to unpack this biodiversity-production mutu- largely ignores farmland biodiversity’s alism (BPM), which bridges the research fields of ecology and agroeconomics and supporting function for high and stable makes the trade-off between food security and protection of biodiversity explicit. yields. By applying the framework, the incorporation of agroecological principles in fi An overhaul of agroeconomic models to global food systems are quanti able, informed assessments of green total factor account for the biodiversity-production productivity (TFP) are supported, and possible lock-ins of the global food system mutualism is urgently needed to answer through overintensification and associated biodiversity loss can be avoided. a question of utmost importance: How do we manage the resources of our planet in such a way that we produce Consequences of Increasing Food Production enough healthy food without destroying our life-support system? The quest for greater crop output for food and non-food products [1–3] leads to both an increase in agricultural land use and an increase in yields, typically achieved through an intensification of culti- A comprehensive analytical framework is vation methods that help to close yield gaps (see Glossary)[4,5,62]. This, in turn, leads to a loss of provided that accounts for multitrophic biodiversity-production processes; brid- biodiversity in agricultural landscapes [7] and increases pressure on natural diversity [8], which con- ges disciplinary boundaries between tinues declining despite ongoing efforts for protection [9]. The avoidance of food waste and dietary agronomy, agroecology, economics, changes offer two demand-side options to reduce pressure on food production [10], but these have and conservation science; and eluci- thus far not been achieved at the macro level [11]. dates the strong interactions of ecosys- tem functioning with food security and malnutrition. Biodiversity is a crucial component of ecosystem functions that are essential for agricultural production, such as soil fertility, pollination, and biocontrol (i.e., the control of plant pests by their nat- 1 – – UFZ Helmholtz Centre for ural enemies) [12 15]. This interdependence of biodiversity and agricultural production has led to a Environmental Research, Department of variety of concepts that aim to optimize the management of agricultural landscapes, balancing yields, Computational Landscape Ecology, biodiversity, and sustainability [16]. These concepts make use of agroecological principles [17], Leipzig, Germany 2Institute of Geoscience and promote organic farming [18] suggest ecological intensification [19], or sustainable intensifi- Geography, Martin-Luther-University cation (SI) [20], compare land sharing and land sparing concepts [21–23] and take the perspec- Halle-Wittenberg, Halle (Saale), Germany 3 tive of managing a coupled socioecological system (SES). While there is much published research on International Food Policy Research Institute, Washington, DC 20005, USA the SES concept, quantitative, empirically-based, and model-based implementations are largely 4Zoological Biodiversity, Institute of lacking or their improvement through process-based validation is pending [24]. As a result, it is cur- Geobotany, Leibniz University Hannover, rently not possible to capture and quantify the biodiversity-production mutualism (BPM) in its entirety. Hannover, Germany 5Department of Agricultural Economics, However, recent research provides the necessary basis for such a comprehensive, quantitative, Purdue University, West Lafayette, IN process-based understanding of the BPM concept [15,24,25]. 47907, USA A Multidisciplinary Perspective on the Relationship between Agriculture and Biodiversity How is Biodiversity Affected by Cropland Management? Management of agricultural landscapes serves the provisioning of agricultural goods and has had *Correspondence: mostly negative impacts on biodiversity [7,8]. This occurs through both the expansion and [email protected] (R. Seppelt). Trends in Ecology & Evolution, Month 2020, Vol. xx, No. xx https://doi.org/10.1016/j.tree.2020.06.012 1 © 2020 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Trends in Ecology & Evolution intensification of cultivated areas, which in turn warps the composition of landscapes and their struc- Glossary fi ture. Conventional intensi cation to increase yields is typically done by homogenizing the landscape Agroecological principles: are (fewer, larger fields), increasing inputs (labor, fertilizer, irrigation, chemicals), and/or augmenting har- supposed to contribute to transforming vest intensities [26–29]. Conventional intensification typically leads to a loss of species present and food systems by applying ecological fi a change in the composition of communities, for example, in the form of a general decrease in abun- principles (ecological intensi cation) to ensure a regenerative use of natural dance [7,8,18]. There is evidence of a long-term decline in insect species due to habitat loss and ag- resources while addressing the need for ricultural intensification [30,31]. This can also be associated with a proportionally greater abundance socially equitable food systems. While of pest species due to a reduction in biological pest control [32]. Ecological intensification directly or the focus initially was on understanding field-level farming practices, now indirectly addresses that trade-off [19,33]; however, a process-based understanding of these rela- landscape-scale processes (such as tionships is context-dependent and, therefore, highly fragmented [34,35]. Homogenization of environ- BPM) as well as the development of mental conditions typically leaves a few abundant generalists, while specialists tend to be lost [24,36]. equitable and sustainable food systems Pests and their predators react differently to the composition of the surrounding landscapes [15]. are considered [17]. fi Closing yield gaps: aims at assessing Consequently, predicting the effects of intensi cation requires careful consideration of multiple factors, differences between observed yields including landscape configuration and species characteristics [25,37,38]. This requires a broader per- and those attainable under comparable spective that includes management of landscapes. bioclimatic conditions. Differences are identified by either statistical or model- Comprehensively Measuring Agricultural Sustainability: Green Total Factor Productivity based comparisons to similar regions [4,5,62]. Critiques: (i) such comparisons The positive effect of intensifying land management on yields is well studied. The relevant range of cannot account for socioeconomic classical reductionist production functions is regarded as positively sloped in input intensification, constraints (prices for inputs and as no rational agent would purchase inputs to reduce production (Figure 1A). However, groups of outputs; access to markets, credit, and technology) and ignore impacts on farmers operating in interlinked agricultural landscapes may find that their individual choices collec- ecosystems and biodiversity; and (ii) tively reduce productivity because each operator ignores the mutualism of biodiversity and production nutritional values are considered implicit, (Figure 4.1 in [39]). Hence, the yield function in intensification may become flat or even turn negatively ‘hidden hunger’, that is, lack of sloped when BPM is considered (Figure 1B). This suggests a revision to agroeconomic models. In micronutrients, unaddressed. Ecological intensification: entails the standard models, each input is usually weighted according to its economic contribution, and an replacement of anthropogenic inputs or index of all outputs can be obtained by weighting each crop according to its share in the total eco- enhancement of crop productivity nomic value. If the output index increases faster than the input index, total factor productivity through fostering biodiversity-based (TFP) increases [40]. TFP was proposed to provide a metric for agricultural sustainability [41,42], ecological functions in agricultural practices [19]. Recent research tends to but since the output and input measures typically cover only those aspects for which markets focus on specificprocesses exist, nonmarket implications are ignored [43]. (e.g., pollination) rather than outcomes (e.g., profits) and results are presented TFP growth can be neutral or beneficial to biodiversity. For example, pest- or disease-resistant at spatiotemporal scales that are less relevant to farmers [33]. varieties can achieve the same yields with reduced use of potentially harmful chemicals. Here, Land sharing: less intense, wildlife the technology
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